This invention relates to a novel and improved high intensity oscillating jet adaptable for cutting hard rock materials such as granite and the like in a rapid and dependable manner.
Various systems have been devised for cutting hard rock materials employing a high intensity jet which will deliver liquid at a sufficiently high pressure and concentration against the surface to form a well defined slit. Typical of this is the method and apparatus set forth in my copending application for patent entitled METHOD & APPARATUS FOR CHANNEL CUTTING OF HARD MATERIALS USING HIGH VELOCITY FLUID JETS, Ser. No. 610, 577, filed 5 Sept. 1975. In that system, a nozzle assembly includes a series of nozzles arranged to form a divergent jet pattern with suspension means for the nozzle assembly which will permit its reciprocation in a direction toward and away from the line to be cut. This system has been found to be particularly effective in forming straight-walled channels or slits for a substantial distance into the material without spalling or substantial jet impedance. Other typical approaches taken to cutting of hard rock materials employing high intensity jets are disclosed in the U.S. Pat. No. 3,883,075, to Edney Noren U.S. Pat. No. 3,960,407 and Sweetman U.S. Pat. No. 2,587,243.
It is desirable to provide a jet cutting system which will afford the deepest possible penetration in forming a well defined slit through the material while permitting the cutting operation to proceed at a relatively high rate of speed. Additionally, it is important that the jets be angled into the groove or slot in such a way as to erode a clear and open bottom for the escape of water and eroded material so as not to impede the direct flow of water against the bottom of the grooves. Moreover, in cutting relatively deep channels, it is desirable to so form the channel as to maintain relatively straight walls and to prevent the channel from narrowing while at the same time concentrating the jet stream across a uniform width.